I've seen quite a few posts and questions concerning DIY CO2 setups and having issues. I'm not going to say that mine is bullet proof and your results may be different. I can say that so far, this one has never failed me and it lasts a good (4) weeks plus. This is monitored by use of drop checkers. So I thought I would post my write up out here in hopes that it may help people in the future. So here it is.

Do It Yourself CO2 Made Easy

Many hobbyists like to have natural plants in their aquariums. Depending on factors such as lighting and the types of plants you keep, you may need or want to add CO2 to your system. However, buying a pressurized setup can be a bit costly. In comes DIY (Do-It-Yourself). Even then, some people think that even this method is cumbersome. Well, here we are going to go from start to finish just to show how simple it really is.

............. 1) In a large saucepan, fill with water and bring to a rolling boil.............. 2) Empty (1) 6oz package of Jell-O in a large mixing bowl.............. 3) When water is boiling, carefully measure out 2 ½ cups............................... a. CAUTION: Contents will be very hot. Be Careful.............. 4) Pour water in bowl with Jell-O and mix thoroughly until well dissolved.............. 5) Pour in sugar and thoroughly mix again until well dissolved.............. 6) Once everything has been dissolved, pour contents in a flat Tupperware container.............. 7) Cover and place in refrigerator.

* Optional Step *
After about two hours in the fridge, the Jell-O should be starting to set. Test with a grain of rice.
- If it sinks to the bottom, it's not firm enough. Place back in fridge and retest later.
- If rice sits on the top or sinks slightly, it should be good enough. Make sure however that Jell-O is still in a liquid state.
- Sprikle 1/8 cup of uncooked rice over the Jell-O. Using a spoon handle or similiar, gently stir the rice into the Jell-O. It should be free floating within the Jell-O
- Place back in fridge to finish setting up.

Step II: Making the Reactor............. While the Jell-O is setting up, let’s make the reactor vessels.

............. Materials: 1 64oz Juice bottle (Ocean Spray seems to be best)........................... 1 20oz Gatorade bottle........................... 4’ CO2 tubing........................... GE Silicone I caulk (optional)............. Tools:..... Cordless drill w/ bits........................... Scissors........................... Case Knife........................... Needle Nose Pliers........................... Toothpick............. 1) Start by thoroughly cleaning both bottles with hot water.............. 2) Remove lids. Drill a 3/16 hole directly in the center of the juice bottle lid. Drill two holes in the smaller water bottle lid.............. * NOTE * For best results, start with a small drill bit to create a pilot hole. Then using other bits, work your way up to 3/16. The 3/16 size is a fraction smaller than the diameter of the tubing and will provide for a tight fit.

............. 3) Using the case knife, carefully trim any shavings left by the drill bit.............. 4) Measure about 2’ of tubing.............. 5) Using scissors cut one end of the tube at an angle.

............. 6) Push the angled end through the top of the cap.............. 7) Using the pliers, grab the end and carefully pull the tubing the rest of the way through the cap.............. 8 ) Cut off the angled end to make a flat cut.............. 9 ) Slowly pull tubing out of cap until about ¼” remains in the cap.............. 10) Repeat steps 5-8 with the opposite end of the tubing into one hole of the water bottle cap.............. 11) Test fit tubing in water bottle and adjust length if needed. There should be a bend in the tubing.............. 12) Using the remaining length of tubing, repeat steps 5-9 using the second hole on the water bottle cap.............. 13) Caulk around all three pieces of tubing on the inside of the caps using GE Silicone I caulk only. This is an optional step as the seal around the tubing will be sufficient with the 3/16” hole depending on how you diffuse the gas. I didn’t do this at first until I switched to a glass diffuser, which resulted in higher pressure build up. In one setup, I discovered a leak in the separator bottle so I added the silicone. Caulk around the tube on the top side of the cap as well.............. 14) Use the toothpick to spread the caulk completely around the tubing to ensure the entire area is covered.............. 15) Set caps aside and let silicone cure at least 24hrs.

Step III: Time to make gas............. Now that our Jell-O has set and our reactor vessels have been made, it is time to start making gas… CO2.

............. Ingredients: ½ tsp Bakers or Brewer’s Yeast divided (¼ tsp. for initial setup / ¼ tsp. to add later).............................. 1 tsp Sugar.............................. 1 cup hot water.............................. ¼ tsp Baking soda.............................. Air stone (diffuser) .............................. * NOTE * use a limewood airstone or for best results, use a glass bell or nano diffuser.............................. * NOTE * - I only use Brewers yeast at the moment as I have found it lasts longer than either Fleischman's or Red Star baking yeast. Again, results may vary.

............. 1) Activate the yeast. In 1 cup hot water, dissolve 1 tsp sugar. Stir thoroughly.............. 2) While water is still spinning from step 1 (tornado effect as I like to call it), carefully pour in ¼ tsp of yeast. This will help in prevent clumping.............. “snow globe” effect shows the yeast activating:............. 3) While this is activating (appox. 15 minutes), cut Jell-O in small cubes. The small cubes allow for more surface action for the yeast.............. 4) Add the cubes to the large bottle.

* Optional Step *
- Using the remaining 1/8 cup of uncooked rice, layer it between the Jell-O. Do this by adding a few cubes of Jell-O to the bottle and then sprinkle a small amount of rice on top. Repeat this process until all rice and Jell-O has been added to the bottle

This write up is a little old now as in the pictures you see a standard water bottle being used for the seperator bottle and a limewood airstone for the diffuser. Both of these have since been replaced with the Gatorade bottle and glass diffusers respectively. I just haven't taken updated pictures to show those.

As mentioned, these will last me 4+ weeks. My drop checkers stay a nice green color throughout. Once I notice them shifting towards the blue end, I will change out the bottles. There is very little, if any, jell-o left in the bottles.